Microcrystalline Y receptor agonists

ABSTRACT

The disclosure provides microcrystals of Y receptor agonists; microcrystalline pellets of Y receptor agonists, and microcrystalline suspensions of Y receptor agonists. Pharmaceutical compositions containing these microcrystals, microcrystalline pellets, and microcrystalline suspensions have prolonged pharmacokinetic profiles making them useful for once daily or once weekly administration.

RELATED APPLICATIONS

This application is a Section 371 of PCT/US2011/043420 filed Jul. 8, 2011, which claims priority to U.S. Application No. 61/363,200 filed Jul. 9, 2010 the disclosure of which is incorporated herein.

FIELD

The disclosure provides compounds, compositions and pharmaceutical formulations of microcrystalline Y receptor agonists.

SEQUENCE LISTING

A computer-readable copy of a sequence listing in text format (.txt) is submitted as part of the specification.

BACKGROUND

Protein crystals have shown significant benefits in the delivery of bioactives to achieve high concentration, low viscosity, extended release profiles, and improved stability. Li et al, Acta Cryst., F63:599-601 (2007); Basu et al, Expert Opin. Biol. Ther., 4(3):301-317 (2004); Yang et al, PNAS, 100(12):6934-6939 (2003). Some proteins and peptides have been crystallized alone or co-crystallized with zinc in an attempt to make extended release products. Y receptor agonists, complex compounds that often possess inadequate stability and short half-life, have limited delivery options. There is a need in the art for formulations of Y receptor agonists that have extended release properties and that have suitable stability. The disclosure is directed to these, as well as other, important ends.

SUMMARY

The disclosure is based on the unexpected discovered that microcrystals of Y receptor agonists may be produced that have extended pharmacokinetic profiles. Therefore, pharmaceutical compositions containing the Y receptor agonists may be administered to the patient once per day, once every other day, or once per week.

The disclosure provides microcrystals of Y receptor agonists, wherein the microcrystals have a particle size from about 1 micron to about 25 microns and are birefringent under a polarized light microscope. In one embodiment, the microcrystals are complexed with metals. In one embodiment, the microcrystals are coated with polyamino. In one embodiment, the microcrystals are complexed with metals and coated with polyamino acids.

The disclosure provides methods for preparing compositions comprising microcrystals of Y receptor agonists by (i) dissolving a Y receptor agonist peptide in an aqueous solution at a pH of about 3 to about 5, wherein the aqueous solution optionally contains a dissolution agent to facilitate dissolution of the Y receptor agonist, to produce a first aqueous solution having the Y receptor agonist peptide dissolved therein; (ii) adjusting the pH of the first aqueous solution upward to a pH of about 4.0 to about 7.5, to produce a second aqueous solution having the Y receptor agonist peptide dissolved therein; and (iii) stirring the second aqueous solution at a temperature from about 1° C. to about 10° C. for more than one day; thereby producing the composition. The compositions may be referred to as microcrystalline suspensions. Following the additional step of drying, the compositions may be referred to as microcrystalline pellets. In one embodiment, the methods may further comprise the addition of metals to form metal complexes of the microcrystals. In one embodiment, the methods may further comprise the addition of polyamino acids to form microcrystals coated with polyamino acids. In one embodiment, the methods may further comprise the addition of metals and polyamino acids to form metal-complexed microcrystals coated with polyamino acids.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a microscopic picture of microcrystals of the Y receptor agonist peptide having SEQ ID NO:438.

FIG. 2 is a polarized light microscopic picture showing that the microcrystals of the Y receptor agonist peptide having SEQ ID NO:438 exhibit birefringence.

FIG. 3 is a microscopic picture of microcrystals of the Y receptor agonist peptide having SEQ ID NO:281.

FIG. 4 is a microscopic picture of microcrystals of the Y receptor agonist peptide having SEQ ID NO:439.

FIG. 5 is a microscopic picture of microcrystalline pellets of the Y receptor agonist peptide having SEQ ID NO:438.

FIG. 6 shows the pK profile (semi-log profile scale) of the following formulations administered to rats: Group 2: a solution containing the peptide of SEQ ID NO:438; Group 3: a microcrystalline suspension containing the peptide of SEQ ID NO:438; Group 4: a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 3:1; and Group 5: a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 1:1.

FIG. 7 shows the body weight loss in rats after a single subcutaneous injection (5 mg/kg) of the following formulations: Group 1: vehicle; Group 2: a solution containing the peptide of SEQ ID NO:438; Group 3: a microcrystalline suspension containing the peptide of SEQ ID NO:438; Group 4: a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 3:1; and Group 5: a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 1:1.

FIG. 8 shows the cumulative food intake on female NH/Swiss mice after a single subcutaneous injection (100 μg/kg) of: (i) vehicle; (ii) a solution containing the peptide of SEQ ID NO:438; (iii) a microcrystalline suspension of the peptide of SEQ ID NO:438; (iv) a poly-L-glutamic acid-coated microcrystalline suspension of peptide of SEQ ID NO:438; and (v) a peptide of SEQ ID NO:438 modified with polyethylene glycol.

FIG. 9 shows the change from base line of food intake on rats (n=8) following a subcutaneous injection (1 mg/kg) of (i) vehicle; (ii) a solution containing the peptide of SEQ ID NO:438; (iii) a microcrystalline suspension of the peptide of SEQ ID NO:438; (iv) a microcrystalline suspension of peptide of SEQ ID NO:438 coated with poly-L-glutamic acid.

DETAILED DESCRIPTION

The disclosure is based on the surprising and advantageous benefits of microcrystals of Y receptor agonist peptides. It has been discovered that microcrystals of Y receptor agonist peptides have improvements with regard to, e.g., increased efficacy, extended pharmacokinetic profile and bioavailability (e.g., allowing for once daily or once weekly administration), and increased stability, relative to that observed with noncrystalline solutions of Y receptor agonist peptides. This results in improved efficacy with regard to, e.g., patient compliance, reductions in body weight, weight loss, reduction in food intake, and beneficial alteration in body composition (e.g., fat-specific weight loss, and/or lean-sparing weight loss), relative to the efficacy observed with noncrystalline solutions of such Y receptor agonists.

The term “microcrystals” refers to Y receptor agonist peptides having a particle size ranging from about 1 micron to about 25 microns. In one embodiment, “microcrystals” refers to Y receptor agonist peptides having a particle size ranging from about 1 micron to about 25 microns, where the microcrystals are birefringent (i.e., have two indices of refraction) under polarized light. In one embodiment, “microcrystals” refers to Y receptor agonist peptides having a particle size ranging from about 1 micron to about 25 microns, where the microcrystals are birefringent (i.e., have two indices of refraction) under polarized light, and where the microcrystals have an alpha-helical structure, a beta-sheet secondary structure, or an alpha-helical structure and a beta-sheet secondary structure when viewed by infrared spectroscopy (e.g., using an FTIR spectrometer). In one embodiment, the microcrystals have a particle size ranging from about 1 micron to about 15 microns. In one embodiment, the microcrystals have a particle size ranging from about 1 micron to about 10 microns. In one embodiment, the microcrystals have a particle size ranging from about 5 microns to about 15 microns. In one embodiment, the microcrystals have a particle size ranging from about 5 microns to about 10 microns. In another embodiment, the microcrystals have (i) oval-shaped crystals; (ii) blade-like crystals; or (iii) oval-shaped crystals and blade-like crystals. Microcrystals are shown in FIGS. 1-5. FIG. 2 shows that the microcrystals are birefringent when viewed under a polarized light microscope. Microcrystals having an oval shape are shown in FIGS. 1 and 3. Microcrystals having a thin blade shape or a blade-like shape are shown in FIG. 4.

The term “microcrystalline pellets” refers to a plurality of microcrystals. Microcrystalline pellets are shown in FIG. 5 (viewed under a microscopic).

The term “microcrystalline suspension” refers to a plurality of microcrystals dispersed or suspended in an aqueous solution. In one embodiment, the term “microcrystalline suspension” refers to microcrystalline pellets that are dispersed or suspended in an aqueous solution.

The term “aqueous solution” is a solution in which the solvent is water. The aqueous solutions described herein may further comprise pharmaceutically acceptable excipients, as described herein.

The microcrystals are prepared by dissolving one or more Y receptor agonist peptides in an aqueous solution having a pH from about 3 to about 5 to produce a first aqueous solution having the Y receptor agonist dissolved therein. The pH of the solution may be adjusted to a pH from about 3 to about 5 using any buffer known in the art. Exemplary buffers include phosphate buffers, acetate buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the first aqueous solution is from about 3.5 to about 4.5.

In one embodiment, the aqueous solution further comprises a dissolution agent to facilitate or enhance dissolution of the Y receptor agonist. Any dissolution agent known in the art may be used. In one embodiment, the dissolution agent is a polyol. Exemplary polyols include glycerol, mannitol, sorbitol, sucrose, glycol, ethylene glycol, pentaerythritol, and the like. In one embodiment, the polyol is glycerol. The amount of dissolution agent used will vary with the particular requirements of any Y receptor agonist.

After the Y receptor agonist is dissolved in the first aqueous solution, then the pH of the first aqueous solution is adjusted upward to a pH of about 4 to about 7.5 to produce a second aqueous solution having the Y receptor agonist dissolved therein. The pH can be adjusted upward using any buffer known in the art. Exemplary buffers include phosphate buffers, Tris buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the second aqueous solution is from about 4 to about 5.5. In one embodiment, the pH of the second aqueous solution is from about 5.5 to about 7.5.

Thereafter, microcrystals are formed by stirring the second aqueous solution at a temperature of about 1° C. to about 10° C. for at least one hour. The microcrystals begin to form during this process, until a plurality of microcrystals develop (substantially maintaining their crystal structure) to form a microcrystalline suspension. In one embodiment, the second aqueous solution is stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the second aqueous solution is stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the second aqueous solution is stirred for at least 12 hours. In one embodiment, the second aqueous solution is stirred for at least one day. In one embodiment, the second aqueous solution is stirred from about one day to about one month. In one embodiment, the second aqueous solution is stirred from about one day to about ten days.

The microcrystalline suspension can be dried to produce microcrystalline pellets.

The final concentration of peptide in the microcrystalline suspension may be from 0.2 mg/mL to 10 mg/mL. The final concentration of peptide in the microcrystalline may be determined by the pH of the second aqueous solution. Generally, when the pH of the second aqueous solution is from 4 to 5.5, the concentration of peptide in the microcrystalline suspension is from 5 mg/mL to 10 mg/mL. Generally, when the pH of the second aqueous solution is from 5.5 to 7.5, the concentration of peptide in the microcrystalline suspension is from 0.2 mg/mL to 5 mg/mL.

As described in the Examples below, the individual microcrystals have structures exemplified in FIG. 1 (viewed under a microscope) and FIG. 2 (exhibiting birefringence when viewed under a polarized light microscope). Upon drying the microcrystalline suspension, the resulting microcrystalline pellets (e.g., plurality or group of microcrystals) have the structures exemplified in FIG. 3.

Pharmaceutical compositions can be prepared using the microcrystalline suspension and/or the microcrystalline pellets. Other pharmaceutically acceptable excipients known in the art and described herein may be added to the pharmaceutical compositions to exhibit the desired pharmaceutical properties.

In another embodiment, the disclosure provides microcrystals of Y receptor agonists coated with polyamino acids. The polyamino acids may be any known in the art. The polyamino acids may be in the form of poly-L-amino acids. Exemplary poly-amino acids include poly-glutamic acid (poly-L-glutamic acid), poly-lysine (poly-L-lysine), poly-arginine (poly-L-arginine), poly-aspartic acid (poly-L-aspartic acid), poly-ornithine (poly-L-ornithine), and the like. In one embodiment, the poly-amino acid is poly-L-glutamic acid. In one embodiment, the microcrystals are coated with two different polyamino acids. The microcrystals can be partially coated, substantially coated, or completely coated with the polyamino acids, depending on the amount of polyamino acid used in the preparation. Similarly, the polyamino acid coating can be any thickness, depending on the amount of polyamino acid used in the preparation. Following the methods described herein, the skilled artisan can vary and optimize the amount of polyamino acid used in the process for coating the microcrystals.

The microcrystals are prepared by dissolving one or more Y receptor agonist peptides in an aqueous solution having a pH from about 3 to about 5 to produce a first aqueous solution having the Y receptor agonist dissolved therein. The pH of the solution may be adjusted using any buffer known in the art. Exemplary buffers include phosphate buffers, acetate buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the first aqueous solution is from about 3.5 to about 4.5. In one embodiment, the aqueous solution further comprises a dissolution agent to facilitate or enhance dissolution of the Y receptor agonist. Any dissolution agent known in the art may be used. In one embodiment, the dissolution agent is a polyol. Exemplary polyols include glycerol, mannitol, sorbitol, sucrose, glycol, ethylene glycol, pentaerythritol, and the like. In one embodiment, the polyol is glycerol.

After the Y receptor agonist is dissolved in the first aqueous solution, then the pH of the first aqueous solution is adjusted upward to a pH of about 4 to about 7.5 to produce a second aqueous solution. The pH can be adjusted upward using any buffer known in the art. Exemplary buffers include phosphate buffers, Tris buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the second aqueous solution is from about 4 to about 5.5. In one embodiment, the pH of the second aqueous solution is from about 5.5 to about 7.5.

Thereafter, microcrystals are formed by stirring the second aqueous solution at a temperature of about 1° C. to about 10° C. for at least one hour. The microcrystals begin to form during this process, until a plurality of microcrystals develop (substantially maintaining their crystal structure) to form a microcrystalline suspension. In one embodiment, the second aqueous solution is stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the second aqueous solution is stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the second aqueous solution is stirred for at least 12 hours. In one embodiment, the second aqueous solution is stirred for at least one day. In one embodiment, the second aqueous solution is stirred from about one day to about one month. In one embodiment, the second aqueous solution is stirred from about one day to about ten days.

During or after formation of the microcrystalline suspension, one or more polyamino acids are added to the microcrystalline suspension at the pH of the microcrystalline suspension and the microcrystalline suspension and the polyamino acids are stirred at a temperature of about 1° C. to about 10° C. for at least one hour. The polyamino acids may be in the form of an aqueous solution at a pH substantially the same as the pH of the microcrystalline suspension. In one embodiment, the polyamino acids are added after formation of the microcrystalline suspension. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred for at least 12 hours. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred for at least one day. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred from about one day to about one month. In one embodiment, the microcrystalline suspension and the polyamino acids are stirred from about one day to about ten days. This results in a microcrystalline suspension where the microcrystals are coated with the polyamino acid. The microcrystalline suspension can then be dried to produce microcrystalline pellets where the microcrystals are coated with the polyamino acid.

The final concentration of peptide in the microcrystalline suspension may be from 0.2 mg/mL to 10 mg/mL. The final concentration of peptide in the microcrystalline may be determined by the pH of the second aqueous solution. Generally, when the pH of the second aqueous solution is from 4 to 5.5, the concentration of peptide in the microcrystalline suspension is from 5 mg/mL to 10 mg/mL. Generally, when the pH of the second aqueous solution is from 5.5 to 7.5, the concentration of peptide in the microcrystalline suspension is from 0.2 mg/mL to 5 mg/mL.

In the methods described herein, the skilled artisan will be able to use an amount of polyamino acid to achieve a weight ratio of peptide:polyamino acid in the range of 1:1 to 10:1. In one embodiment, the weight ratio of peptide:polyamino acid may be in the range of 2:1 to 6:1. In one embodiment, the weight ratio of peptide:polyamino acid may be in the range of 4:1 to 6:1.

Pharmaceutical compositions can be prepared using the polyamino acid-coated microcrystalline suspension and/or the polyamino acid-coated microcrystalline pellets. Other pharmaceutically acceptable excipients may be added to the pharmaceutical compositions to exhibit the desired pharmaceutical properties. In one embodiment, the pharmaceutically acceptable excipient is a preservative, such as meta-cresol.

The disclosure provides microcrystals complexed with one or more metals. The metals are generally in the form of salts. The metals are preferably alkaline earth metals, transition metals or a combination thereof. Exemplary transition metals include zinc, iron, nickel, copper, and the like. Exemplary alkaline earth metals include calcium, magnesium, and the like. In one embodiment, the microcrystals are complexed with zinc, magnesium, calcium, or a combination of two or more thereof. In one embodiment, the microcrystals are complexed with zinc.

The microcrystals are prepared by dissolving one or more Y receptor agonist peptides in an aqueous solution having a pH from about 3 to about 5 to produce a first aqueous solution having the Y receptor agonist dissolved therein. The pH of the solution may be adjusted using any buffer known in the art. Exemplary buffers include phosphate buffers, acetate buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the first aqueous solution is from about 3.5 to about 4.5. In one embodiment, the aqueous solution further comprises a dissolution agent to facilitate or enhance dissolution of the Y receptor agonist. Any dissolution agent known in the art may be used. In one embodiment, the dissolution agent is a polyol. Exemplary polyols include glycerol, mannitol, sorbitol, sucrose, glycol, ethylene glycol, pentaerythritol, and the like. In one embodiment, the polyol is glycerol.

Thereafter, one or more metals, preferably in the form of the metal salt, are added to the first aqueous solution. Then the pH of the first aqueous solution is adjusted upward to a pH of about 4 to about 7.5 to produce a second aqueous solution. The pH can be adjusted using any buffer known in the art. Exemplary buffers include phosphate buffers, Tris buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the second aqueous solution is from about 4 to about 5.5. In one embodiment, the pH of the second aqueous solution is from about 5.5 to about 7.5.

Thereafter, microcrystals complexed with the metals are formed by stirring the second aqueous solution at a temperature of about 1° C. to about 10° C. for at least one hour. The metal-complexed microcrystals begin to form during this process, until a plurality of metal-complexed microcrystals develop (substantially maintaining their crystal structure) to form a metal-complexed microcrystalline suspension. In one embodiment, the second aqueous solution is stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the second aqueous solution is stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the second aqueous solution is stirred for at least 12 hours. In one embodiment, the second aqueous solution is stirred for at least one day. In one embodiment, the second aqueous solution is stirred from about one day to about one month. In one embodiment, the second aqueous solution is stirred from about one day to about ten days.

The final concentration of peptide in the microcrystalline suspension may be from 0.2 mg/mL to 10 mg/mL. The final concentration of peptide in the microcrystalline may be determined by the pH of the second aqueous solution. Generally, when the pH of the second aqueous solution is from 4 to 5.5, the concentration of peptide in the microcrystalline suspension is from 5 mg/mL to 10 mg/mL. Generally, when the pH of the second aqueous solution is from 5.5 to 7.5, the concentration of peptide in the microcrystalline suspension is from 0.2 mg/mL to 5 mg/mL.

Based on the methods described herein, the skilled artisan will be able to use an amount of metal to achieve a weight ratio of peptide:metal of 1:1 to 10:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 5:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 4:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 3:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 2:1. In one embodiment, the weight ratio of peptide:metal is 3:1. In one embodiment, the weight ratio of peptide:metal is 2:1. In one embodiment, the weight ratio of peptide:metal is 1:1.

Pharmaceutical compositions can be prepared using the metal-complexed microcrystalline suspension and/or the metal-complexed microcrystalline pellets. Other pharmaceutically acceptable excipients may be added to the pharmaceutical compositions to exhibit the desired pharmaceutical properties. In one embodiment, the pharmaceutically acceptable excipient is a preservative, such as meta-cresol.

The disclosure provides microcrystals complexed with one or more metals and coated with polyamino acids. The metals are generally in the form of salts. The metals are preferably alkaline earth metals, transition metals or a combination thereof. Exemplary transition metals include zinc, iron, nickel, copper, and the like. Exemplary alkaline earth metals include calcium, magnesium, and the like. In one embodiment, the microcrystals are complexed with zinc, magnesium, calcium, or a combination of two or more thereof. In one embodiment, the microcrystals are complexed with zinc. The polyamino acids may be any known in the art. The polyamino acids may be in the form of poly-L-amino acids. Exemplary poly-amino acids include poly-glutamic acid (poly-L-glutamic acid), poly-lysine (poly-L-lysine), poly-arginine (poly-L-arginine), poly-aspartic acid (poly-L-aspartic acid), poly-ornithine (poly-L-ornithine), and the like. In one embodiment, the poly-amino acid is poly-L-glutamic acid. In one embodiment, the microcrystals are coated with two different polyamino acids. The microcrystals can be partially coated, substantially coated, or completely coated with the polyamino acids, depending on the amount of polyamino acid used in the preparation. Similarly, the polyamino acid coating can be any thickness, depending on the amount of polyamino acid used in the preparation. Following the methods described herein, the skilled artisan can vary and optimize the amount of polyamino acid used in the process for coating the microcrystals.

The microcrystals are prepared by dissolving one or more Y receptor agonist peptides in an aqueous solution having a pH from about 3 to about 5 to produce a first aqueous solution having the Y receptor agonist dissolved therein. The pH of the solution may be adjusted using any buffer known in the art. Exemplary buffers include phosphate buffers, acetate buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the first aqueous solution is from about 3.5 to about 4.5. In one embodiment, the aqueous solution further comprises a dissolution agent to facilitate or enhance dissolution of the Y receptor agonist. Any dissolution agent known in the art may be used. In one embodiment, the dissolution agent is a polyol. Exemplary polyols include glycerol, mannitol, sorbitol, sucrose, glycol, ethylene glycol, pentaerythritol, and the like. In one embodiment, the polyol is glycerol.

Thereafter, one or more metals, preferably in the form of the metal salt, are added to the first aqueous solution. Then the pH of the first aqueous solution is adjusted upward to a pH of about 4 to about 7.5 to produce a second aqueous solution. The pH can be adjusted using any buffer known in the art. Exemplary buffers include phosphate buffers, Tris buffers, citrate buffers, glutamate buffers, and the like. In one embodiment, the buffer is a phosphate buffer. In one embodiment, the pH of the second aqueous solution is from about 4 to about 5.5. In one embodiment, the pH of the second aqueous solution is from about 5.5 to about 7.5.

Thereafter, microcrystals complexed with the metals are formed by stirring the second aqueous solution at a temperature of about 1° C. to about 10° C. for at least one hour. The metal-complexed microcrystals begin to form during this process, until a plurality of metal-complexed microcrystals develop (substantially maintaining their crystal structure) to form a metal-complexed microcrystalline suspension. In one embodiment, the second aqueous solution is stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the second aqueous solution is stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the second aqueous solution is stirred for at least 12 hours. In one embodiment, the second aqueous solution is stirred for at least one day. In one embodiment, the second aqueous solution is stirred from about one day to about one month. In one embodiment, the second aqueous solution is stirred from about one day to about ten days.

During or after formation of the metal-complexed microcrystalline suspension, one or more polyamino acids are added to the metal-complexed microcrystalline suspension at the pH of the metal-complexed microcrystalline suspension and the metal-complexed microcrystalline suspension and the polyamino acids are stirred at a temperature of about 1° C. to about 10° C. for at least one hour. The polyamino acids may be in the form of an aqueous solution at a pH substantially the same as the pH of the metal-complexed microcrystalline suspension. In one embodiment, the polyamino acids are added after formation of the metal-complexed microcrystalline suspension. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred at a temperature from about 1° C. to about 8° C. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred at a temperature from about 3° C. to about 6° C. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred for at least 12 hours. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred for at least one day. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred from about one day to about one month. In one embodiment, the metal-complexed microcrystalline suspension and the polyamino acids are stirred from about one day to about ten days. This results in a metal-complexed microcrystalline suspension where the metal-complexed microcrystals are coated with the polyamino acid. The polyamino acid-coated, metal-complexed microcrystalline suspension can then be dried to produce microcrystalline pellets where the microcrystals are complexed with metals and coated with the polyamino acid.

The final concentration of peptide in the microcrystalline suspension may be from 0.2 mg/mL to 10 mg/mL. The final concentration of peptide in the microcrystalline may be determined by the pH of the second aqueous solution. Generally, when the pH of the second aqueous solution is from 4 to 5.5, the concentration of peptide in the microcrystalline suspension is from 5 mg/mL to 10 mg/mL. Generally, when the pH of the second aqueous solution is from 5.5 to 7.5, the concentration of peptide in the microcrystalline suspension is from 0.2 mg/mL to 5 mg/mL. In the methods described herein, the skilled artisan will be able to use an amount of polyamino acid to achieve a weight ratio of peptide:polyamino acid in the range of 1:1 to 10:1. In one embodiment, the weight ratio of peptide:polyamino acid may be in the range of 2:1 to 6:1. In one embodiment, the weight ratio of peptide:polyamino acid may be in the range of 4:1 to 6:1. Based on the methods described herein, the skilled artisan will be able to use an amount of metal to achieve a weight ratio of peptide:metal of 1:1 to 10:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 5:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 4:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 3:1. In one embodiment, the weight ratio of peptide:metal is 1:1 to 2:1. In one embodiment, the weight ratio of peptide:metal is 3:1. In one embodiment, the weight ratio of peptide:metal is 2:1. In one embodiment, the weight ratio of peptide:metal is 1:1.

Pharmaceutical compositions can be prepared using the polyamino acid-coated, metal-complexed microcrystalline suspension and/or the polyamino acid-coated, metal-complexed microcrystalline pellets. Other pharmaceutically acceptable excipients may be added to the pharmaceutical compositions to exhibit the desired pharmaceutical properties. In one embodiment, the pharmaceutically acceptable excipient is a preservative, such as meta-cresol.

Any Y receptor agonist peptide known in the art may be used to form the microcrystals described herein. Exemplary Y receptor agonist peptides are described in, e.g., U.S. Pat. No. 7,723,471; US Publication No. 2006/0094653; US Publication No. 2010/0099619; PCT Publication No. WO 2009/138511; PCT Publication No. WO 2011/033068; or PCT Publication No. WO 2011/058165, the disclosures of which are incorporated by reference herein.

In one embodiment, the Y receptor agonist peptide is PYY(3-36) (SEQ ID NO:3). In one embodiment, the Y receptor agonist is a PYY analog.

“PYY analog” refers to a peptide that has at least 70%, at least 80%, at least 85%, at least 90%o, at least 94%, or at least 97% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the PYY analog has at least 80% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the PYY analog has at least 85% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the PYY analog has at least 90% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the PYY analog has at least 94% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the PYY analog has at least 97% sequence identity to PYY(3-36) over the entire length of PYY(3-36).

In one embodiment, the PYY analog may be a chimeric peptide. In this emobodiment, PYY(3-36) (SEQ ID NO:3) may comprise amino acid sequences from the pancreatic polypeptide (“PP”) (SEQ ID NO: 1) and/or neuropeptide Y (SEQ ID NO:4) in order to vary the properties of the peptide.

In other embodiments, the PYY analogs may be from 30 to 36 amino acids in length; preferably from 32 to 34 amino acids in length. The skilled artisan will appreciate that PYY analogs may be prepared by the addition of amino acids to the amino acid sequence of PYY(3-36) (e.g., at the C-terminus, N-terminus, within the peptide, or a combination thereof); the deletion of amino acids from the amino acid sequence of PYY(3-36) (e.g., at the C-terminus, N-terminus, within the peptide, or a combination thereof); substitutions of any of the amino acids for different amino acids in the amino acid sequence in PYY(3-6); or a combination of two or more of additions, deletions, and substitutions. As used herein, the term “substitution” includes modifications made to an amino acid (e.g., an amino acid is substituted with a modified version of the original amino acid). Typical modifications to amino acids include amides, carbohydrates, alkyl groups, acyl groups, fatty acyl groups, esters, and the like.

Exemplary Y receptor agonists are set forth in the Sequence Listing submitted herewith as part of the specification and incorporated by reference herein. Such Exemplary Y receptor agonists include SEQ ID NOs: 1-483. These Y receptor agonist peptides are also described in U.S. Pat. No. 7,723,471.

In one embodiment the PYY analog has the amino acid sequence of SEQ ID NO:483:

Xaa₁ Lys Pro Glu Xaa₅ Pro Gly Glu Asp Ala Ser Pro Xaa₁₃ Glu Glu Leu Ala Arg

Tyr Tyr Xaa₂₁ Xaa₂₂ Leu Arg Xaa₂₅ Tyr Ile Asn Leu Ile Thr Arg Gin Arg Xaa₃₅, wherein Xaa₁ is Ile, isocaproyl-Ile, Pro, or isocaproyl-Pro; Xaa₅ is His or Ala; Xaa₁₃ is Ala or absent; Xaa₂₁ is Ala or Ser; Xaa₂₂ is Ser or Ala; Xaa₂₅ is Ala or His; and Xaa₃₅ is Tyr-OH or Tyr-NH₂.

In one embodiment, the peptide of SEQ ID NO:483 is SEQ ID NO:438: Pro Lys Pro Glu His Pro Gly Glu Asp Ala Ser Pro Glu Glu Leu Ala Arg Tyr Tyr Ala Ser Leu Arg Ala Tyr Ile Asn Leu Ile Thr Arg Gin Arg Tyr (SEQ ID NO:438).

In one embodiment, the peptide of SEQ ID NO:483 is SEQ ID NO:281: isocaproyl-Ile Lys Pro Glu Ala Pro Gly Glu Asp Ala Ser Pro Glu Glu Leu Ala Arg Tyr Tyr Ser Ala Leu Arg His Tyr Ile Asn Leu Ile Thr Arg Gin Arg Tyr (SEQ ID NO:281).

In one embodiment, the peptide of SEQ ID NO:483 is SEQ ID NO:439: Pro Lys Pro Glu His Pro Gly Glu Asp Ala Ser Ala Glu Glu Leu Ala Arg Tyr Tyr Ala Ser Leu Arg Ala Tyr Ile Asn Leu Ile Thr Arg Gin Arg Tyr (SEQ ID NO:439).

In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:30. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:88. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:348. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:349. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:350. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:481. In one embodiment, the Y Receptor agonist comprises the amino acid sequence of SEQ ID NO:482.

In one embodiment, the Y receptor agonist is a PYY analog that has at least 70% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the Y receptor agonist is a PYY analog that has at least 80% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the Y receptor agonist is a PYY analog that has at least 85% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the Y receptor agonist is a PYY analog that has at least 90% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the Y receptor agonist is a PYY analog that has at least 94% sequence identity to PYY(3-36) over the entire length of PYY(3-36). In one embodiment, the Y receptor agonist is a PYY analog that has at least 97% sequence identity to PYY(3-36) over the entire length of PYY(3-36).

In one embodiment, the Y receptor agonist is a compound described in PCT Publication No. WO 2009/138511. In one embodiment, the Y receptor agonist is a compound described in PCT Publication No. WO 2011/033068. In one embodiment, the Y receptor agonist is a compound described in WO 2011/058165

The Y receptor agonist peptides described herein may be formulated as pharmaceutically acceptable salts (e.g., acid addition salts) and/or complexes thereof. Pharmaceutically acceptable salts include acid addition salts such as those containing sulfate, hydrochloride, phosphate, sulfamate, acetate, citrate, lactate, tartrate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, cyclohexylsulfamate and quinate. Pharmaceutically acceptable salts can be obtained from acids such as hydrochloric acid, sulfuric acid, phosphoric acid, sulfamic acid, acetic acid, citric acid, lactic acid, tartaric acid, malonic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, cyclohexylsulfamic acid, and quinic acid. Such salts may be prepared by, for example, reacting the free acid or base forms of the product with one or more equivalents of the appropriate base or acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is then removed in vacuo or by freeze-drying or by exchanging the ions of an existing salt for another ion on a suitable ion exchange resin.

The compositions and pharmaceutical compositions described herein may be provided in any form suitable for administration to a patient. In one embodiment, the pharmaceutical compositions are in a form suitable for oral administration. In one embodiment, the pharmaceutical compositions are in a form suitable for parenteral administration. Exemplary forms of parenteral administration include infusion, intravenous, intramuscular, subcutaneous, and the like. In one embodiment, the compositions and pharmaceutical formulations are provided in a form suitable for subcutaneous injection. The compositions and pharmaceutical compositions may be formulated with known pharmaceutically acceptable excipients, e.g., Remington's Pharmaceutical Sciences by E. W. Martin, including an aqueous solution.

Exemplary pharmaceutically acceptable excipients include buffers, isotonicity agents, preservatives, emulsifying agents, surfactants, chelating-agents, dissolution enhancing agents, and the like. Buffers include, for example, citrate buffers, acetate buffers, phosphate buffers, glutamate buffers, and the like. Isotonicity agents include, for example, sodium chloride, dextrose, boric acid, sodium tartrate, propylene glycol, polyols, or other inorganic or organic solutes. Emulsifying agents include, for example, acacia powder, a non-ionic surfactant, or an ionic surfactant). Preservatives include, for example, meta-cresol, sodium benzoate, potassium sorbate, phenol, methyl-paraben, ethyl-paraben, propyl-paraben, butyl-paraben, and the like. Other pharmaceutically acceptable excipients include, for example, calcium carbonate, calcium phosphate, sugars (e.g., lactose, glucose, sucrose), starch, cellulose derivatives, gelatin, vegetable oils, polyethylene glycol, and the like. The skilled artisan will appreciate that pharmaceutical compositions may contain one more excipients necessary to achieve the desired properties.

The pharmaceutical compositions described herein comprise the Y receptor agonist in therapeutically effective amounts. Typically, therapeutically effective amounts will be in the range of about 0.1 μg to about 10 mg/day; about 1 μg to about 5 mg/day; about 100 μg to about 1 mg/day; or about 5 μg to about 500 μg/day. The exact dose to be administered may be determined by one of skill in the art and is dependent upon the potency of the particular compound, as well as upon the age, weight and condition of the individual.

It was unexpectedly discovered that the microcrystals of Y receptor agonists have extended pharmacokinetic (pK) profiles. Therefore, the pharmaceutical compositions containing the Y receptor agonists may be administered to the patient once per day, once every other day, or once per week.

The compounds, compositions, and pharmaceutical compositions described herein may be used to treat any disease known in the art for which therapy with Y receptor agonists is appropriate. Exemplary diseases that may be treated using the compounds, compositions, and pharmaceutical compositions described herein include diabetes (e.g., type 1 diabetes, type 2 diabetes, gestational diabetes, pre-diabetes); obesity; overweight; fatty liver diseases (e.g., non-alcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD)); gastrointestinal diseases (e.g., ulcerative colitis, diarrhea, short bowel syndrome, small intestinal bacterial overgrowth, irritable bowel syndrome, Crohn's disease); gallbladder disease, hypertension, dyslipidemia, cardiovascular disease, myocardial infarction, atherosclerosis, eating disorders, insulin-resistance, and the like. In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to treat diabetes (e.g., type 1 diabetes, type 2 diabetes, gestational diabetes, pre-diabetes) in a patient. The diabetes is preferably type 2 diabetes. In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to treat obesity in a patient. In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to treat overweight in a patient. In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to treat fatty liver diseases (e.g., non-alcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) in a patient. In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to treat gastrointestinal diseases (e.g., ulcerative colitis, diarrhea, short bowel syndrome, irritable bowel syndrome, Crohn's disease, gallbladder disease) in a patient.

The compounds, compositions, and pharmaceutical compositions described herein may also be used to reduce body weight; reduce caloric intake; reduce food intake; slow gastric emptying; inhibit gastric acid secretion; lower triglycerides; lower LDL cholesterol; inhibit pancreatic enzyme secretion; and alter body composition (e.g., decrease fat and increase lean muscle). In one embodiment, the compounds, compositions, and pharmaceutical compositions described herein are used to reduce the body weight of a patient.

Each of the diseases and conditions described herein is known in the art and the art-recognized meaning and definition are intended to apply. Such diseases that can be treated with Y receptor agonists are described, for example, in U.S. Pat. No. 7,723,471; US Publication No. 2006/0094653; US Publication No. 2010/0099619; PCT Publication No. WO 2009/138511; PCT Publication No. WO 2011/033068; or PCT Publication No. WO 2011/058165, the disclosures of which are incorporated by reference herein.

EXAMPLES

The following examples are for purposes of illustration and are not intended to limit the scope of the claims.

Example 1

Y receptor agonists having SEQ ID NOs:438, 281 and 439 were synthesized by known methods (e.g., U.S. Pat. No. 7,723,471) and purified by HPLC to a purity greater than 90%.

Example 2

SEQ ID NO:438 in the form of an acetate salt was dissolved in 30 mM, pH 3 phosphate solution with 1.76% glycerol and 0.22% meta-cresol, and aseptically filtered through a 0.22 μm filter. The pH was then adjusted upward to pH 7.2±0.2 with 1 N sodium hydroxide solution. The total weight of the solution was adjusted to the target weight using 30 mM, pH 7.2 phosphate buffer with 1.76% glycerol and 0.22% meta-cresol. A microcrystalline suspension was obtained after stirring at a temperature of about 5° C. for 7 days. The resulting concentration of peptide having SEQ ID NO:438 was 2 mg/mL.

The morphology of the microcrystals was examined under microscope with or without polarized light. The crystals were oval shaped, as shown in FIG. 1. Under polarized light, the crystals exhibited birefringence, as shown in FIG. 2. The shape and surface morphology collected from the microcrystalline suspension were confirmed by SEM. The particle size was determined to be about 5-10 microns. The FTIR spectrum exhibited both alpha-helical and beta-sheet secondary structural characteristics in the solid crystals. Additionally, the FTIR spectrum of the solid crystals showed no significant difference compared to the original fluffy, amorphous powder prior to crystallization.

The skilled artisan will appreciate that microcrystalline suspension with a final concentration of SEQ ID NO:438 in the range of 0.2 mg/mL to 10 mg/mL can be prepared by varying the amount of SEQ ID NO:438 acetate and phosphate buffer.

Example 3

A microcrystalline suspension comprising peptides having SEQ ID NO:281 were prepared as described in Example 2, except that the pH was adjusted from pH 3 upward to a pH between 4 and 5.5. The concentration of peptides having SEQ ID NO:281 in the microcrystalline suspension was 5-10 mg/ml. In this example, a microcrystalline suspension of the peptide having a concentration in the range of 0.2 to 5 mg/mL could be formed at a higher pH range of 5.5 to 7.5 (rather than the pH of 4 to 5.5 that was used).

Example 4

A microcrystalline suspension comprising peptides having SEQ ID NO:439 was prepared as described in Example 2, except that the pH was adjusted from pH 3 upward to a pH from 6.5 to 7.4. The concentration of peptides having SEQ ID NO:439 in the buffered solution was 2 mg/ml.

Example 5

SEQ ID NO:438 acetate was dissolved in 30 mM, pH 3 phosphate solution with 1.76% glycerol and 0.22% meta-cresol, and aseptically filtered through a 0.22 μm filter. Zinc acetate solution was aseptically filtered and added to the solution. The pH was then adjusted upward to pH 7.2±0.2 with 1 N sodium hydroxide solution. The total weight of the solution was adjusted to the target weight using 30 mM, pH 7.2 phosphate buffer with 1.76% glycerol and 0.22% meta-cresol. A zinc-complexed microcrystalline suspension was obtained after constant stirring at a temperature of about 5° C. for 7 days. The final concentration of peptide was 2 mg/mL, and the weight ratio of peptide:zinc was 3:1.

The final concentration of the peptide having SEQ ID NO:438 in the microcrystalline suspension having a range of 0.2-10 mg/mL can be prepared by varying the amount of SEQ ID NO:438 acetate, phosphate buffer, and zinc acetate. Additionally, the weight ratio of peptide:zinc can be modified by varying the amount of zinc added to the solution.

Example 6

The microcrystalline suspensions of SEQ ID NO:438 without zinc (e.g., Example 2) and with zinc (e.g., Example 5) were administered to male Sprague-Dawley rats (12 per formulation) by single subcutaneous injection at 5 mg/kg dose. Vehicle (phosphate buffer) and a solution containing SEQ ID NO:438 were used as controls. Blood samples were collected at various time points from 0.25 to 72 hours post injection. Plasma concentrations of the peptide were determined by an immunoenzymetric assay (IEMA). PK parameters were calculated using WinNonlin Professional software.

The results of the pK study are shown in FIG. 6. The results of the body weight study are shown in FIG. 7. With reference to FIGS. 6 and 7: Group 1 was administered a phosphate buffer, pH 7.2, vehicle; Group 2 was administered a solution containing the peptide of SEQ ID NO:438; Group 3 was administered a microcrystalline suspension containing the peptide of SEQ ID NO:438; Group 4 was administered a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 3:1; and Group 5 was administered a zinc-complexed microcrystalline suspension of the peptide of SEQ ID NO:438, where the ratio of peptide:zinc was 1:1.

FIGS. 6 and 7 demonstrate that the results of rat PK and efficacy studies using microcrystalline suspensions of SEQ ID NO: 438 showed sustained release of the microcrystalline suspensions compared to vehicle and the solution containing SEQ ID NO:438. The mean plasma concentration of the peptide dropped to 2000 pg/mL at 8 hours post injection for the control solution, while it took 72 hours to drop to that same level for the microcrystalline suspensions. The rats that received the microcrystalline suspensions showed approximately 10% more body weight loss than the controls (vehicle and peptide solution) by single subcutaneous injection. The pK profile and weight loss efficacy of the microcrystalline suspension was not statistically significantly different from that of the zinc-complexed microcrystalline suspension.

Example 7

A poly-L-glutamic acid solution was prepared as follows. Poly-L-glutamic acid was dissolved in purified and de-ionized water. The pH was adjusted to pH 7.2 with IN sodium hydroxide solution.

SEQ ID NO:438 acetate was dissolved in 30 mM, pH 3 phosphate solution with 1.76% glycerol and 0.22% meta-cresol, and aseptically filtered through a 0.22 μm filter. The pH was then adjusted upward to pH 7.2±0.2 with 1 N sodium hydroxide solution. The total weight of the solution was adjusted to the target weight using 30 mM, pH 7.2 phosphate buffer with 1.76%) glycerol and 0.22% meta-cresol. A microcrystalline suspension was obtained after stirring at 5° C. for 7 days.

Thereafter, the poly-L-glutamic acid solution at pH 7.2 was added to the microcrystalline suspension while stirring. Poly-L-glutamic acid-coated microcrystalline suspension was formed after constant stirring at 5° C. for 4 days. The final concentration of peptide was 2 mg/mL and the weight ratio of peptide to poly-L-glutamic acid was 5:1.

Poly-L-glutamic acid-coated microcrystalline suspension with a final concentration of SEQ ID NO:438 in the range of 1-10 mg/mL can be prepared by varying the amount of SEQ ID NO:438 acetate, phosphate buffer, and poly-L-glutamic acid.

Example 8

Animal studies were undertaken to compare the formulations described herein for effects on food intake. The following formulations were used: (1) vehicle/placebo containing 30 mM phosphate buffer with 1.76% glycerol at pH 7.2; (ii) solution containing the peptide of SEQ ID NO:438; 4.9% mannitol, 0.07% Tween 80; and a 10 mM acetate buffer, at a pH 4.3; (iii) the microcrystalline suspension of Example 2; (iv) the polyamino acid-coated microcrystalline suspension of Example 7; and (v) a solution of a pegylated peptide, i.e., the peptide of SEQ ID NO:438 modified with K¹¹ conjugated to a linear polyethylene glycol having a molecular weight of 20 kilodaltons. The formulations were injected subcutaneously (100 μg/kg) into overnight-fasted female NIH/Swiss mice. Food was introduced immediately after injection and the amount consume was measured at 30 minutes, 60 minutes, 120 minutes, 180 minutes, 240 minutes, 300 minutes, 360 minutes, 24 hours, 30 hours, 48 hours, 56 hours, and 72 hours. The results for cumulative food intake are shown in FIG. 8 (*p<0.05 vs. vehicle control; ANOVA, Dunnett's test). The results for the change in food intake from baseline are shown in FIG. 9 (*p<0.05 compared to placebo; ^p<0.05 compared to solution containing the peptide of SEQ ID NO:438; 4.9% mannitol, 0.07% Tween 80; and a 10 mM acetate buffer, at a pH 4.3). 

What is claimed is:
 1. A microcrystal comprising a Y receptor agonist peptide, wherein the microcrystal has a particle size of about 1 micron to about 15 microns and is birefringent when viewed under a polarized light microscope, wherein the Y receptor agonist peptide comprises the amino acid sequence of any one of SEQ ID NOs: 1-483.
 2. The microcrystal of claim 1, wherein the Y receptor agonist peptide has at least 80% sequence identity to the amino acid sequence of SEQ ID NO:3 (PYY(3-36)):IKPEAPGEDASPEELNRYYASLRHYLNLVTRQRY.
 3. A pharmaceutical composition comprising a plurality of microcrystals according to claim
 1. 4. The pharmaceutical composition of claim 3 further comprising an aqueous solution.
 5. The pharmaceutical composition of claim 4, further comprising a polyol.
 6. The pharmaceutical composition of claim 5, wherein the polyol is glycerol, mannitol, sorbitol, sucrose, glycol, ethylene glycol, pentaerythritol, or a combination thereof.
 7. A method for treating diabetes, overweight, obesity, fatty liver disease, a gastrointestinal disease, hypertension, dyslipidemia, cardiovascular disease, a myocardial infarction, atherosclerosis, an eating disorder, or insulin-resistance in a patient in need thereof comprising administering a therapeutically effective amount of the pharmaceutical composition of claim
 3. 8. The microcrystal of claim 1, wherein the Y receptor agonist peptide comprises the amino acid sequence of SEQ ID NO:281, 438,
 439. 9. The microcrystal of claim 1, wherein the Y receptor agonist peptide comprises the amino acid sequence of SEQ ID NO:
 438. 